Alteration of the disruptive effect of fenfluramine on food consumption in the rat by repeated post-session administration of d-amphetamine.
The purpose of this study was to determine whether repeated treatment (15 days) with d-amphetamine (AMP) or fenfluramine (FEN), administered after a daily 3 h feeding session (e.g. post-session), would result in tolerance or cross-tolerance to the decrement in food consumption induced by treatment with either drug before feeding (e.g. pre-session). Groups of males rats were treated IP with 0.5 ml saline, 1.0, 2.0, or 4.0 mg/kg AMP, or 2.5, 5.0, or 10.0 mg/kg FEN prior to a 3 h feeding session. For the next 15 sessions, the respective groups were treated post-session with saline (0.5 ml), AMP (4.0 mg/kg), or FEN (10 mg/kg). Following this 15 day post-session phase, each group again received this pre-session treatment. The initial pre-session treatment with all dosages of these two drugs produced a significant decrease in food consumption. Tolerance to the food intake suppressant effect of FEN, but not AMP, resulted from repeated post-session treatment with the same agent. Repeated post-session treatment with AMP resulted in a significant decrement in the suppressant activity of FEN on food intake, whereas the corresponding post-session treatments with FEN did not alter the pre-session effects of AMP except for an enhancement seen with higher AMP doses.
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003913:Dextroamphetamine / Q000494:pharmacology*; D004347:Drug Interactions; D004361:Drug Tolerance; D005247:Feeding Behavior / Q000187:drug effects*; D005277:Fenfluramine / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D005277:Fenfluramine; D003913:Dextroamphetamine